Probe cleaner and cleaning method

ABSTRACT

A probe cleaner for removing foreign objects from the tip part of a probe is formed with a cleaner sheet having a surface part with microfibers and abrading particles affixed to the surface of the microfibers at this surface part. The average fiber diameter of the microfibers is in the range of 0.1 μm or more and 20 μm or less. The average particle diameter of the abrading particles is in the range of 0.05 μm or more and 3.0 μm or less. For cleaning the tip part of a probe, the probe cleaner is set to the surface of a table, the tip part of the probe is caused to penetrate inside the surface part, and the probe is caused to undergo a reciprocal motion in the direction of the thickness of the surface part.

This application claims priority on Japanese Patent Application2006-250342 filed Sep. 15, 2006.

BACKGROUND OF THE INVENTION

This invention relates to a probe cleaner and a cleaning method forcleaning the tip part of a needle-shaped object such as a probe for theinspection of electric properties, a needle for a clinical use and aknitting needle in the finishing step of the production process orbefore and after a use. This invention relates in particular to such aprobe cleaner and cleaning method for removing foreign objects attachedto the tip part of a probe used for the inspection of electricproperties in the inspection process of a semiconductor device.

In order to improve the production efficiency in the production processof semiconductor devices, a probe is used to contact electrode pads of aplurality of chips formed on a semiconductor wafer for inspecting theelectrical characteristics of each chip by applying and detecting testsignals through this probe.

In general, such a probe is made of a hard material such as tungsten andberyllium, while the electrode pads are made of a relatively softmaterial such as aluminum. When the probe is made to contact anelectrode pad, foreign objects such as aluminum of the electrode padbecome attached to the tip part (the tip and the side surfaces near thetip) of the probe, and this affects the accuracy of the inspectionadversely. If a large foreign object is attached to a probe, mutuallyadjacent probes may become shorted, causing chips to be destroyed. Forthis reason, the tip part of the probe is cleaned for removing suchforeign objects.

As disclosed in Japanese Patent Publications Tokkai 7-244074 and2004-140013, for example, the tip part of a probe may be cleaned byusing a probe cleaner comprising a cleaner sheet made of an elasticmaterial such as silicon rubber and urethane rubber with abradingparticles (such as hard particles of aluminum oxide, silicon carbide anddiamond) mixed in and by causing the tip part of the probe to penetrateinto the interior of this probe cleaner from its surface such that theabrading particles affixed to the elastic material will work on the tippart of the probe.

As disclosed in Japanese Patent Publication Tokuhyo 2005-515645,furthermore, a probe cleaner comprising a cleaner sheet having a stickygel layer formed on the surface of a plate with minute unevennessprepared thereon has also been used. After the tip part of the probepenetrates into the interior of the gel layer from its surface, theprobe is moved while its tip remains in contact with the unevenness ofthe surface of the plate such that the tip part becomes cleaned.

As the chip size is made smaller in recent years, the electrode padsformed on the chips are becoming smaller and the electrode pads arecoming to be formed closer to one another. For this reason, it isbecoming necessary to make the probes thin, and relatively softmaterials having improved electrical characteristics such asberyllium-copper alloys are coming to be used to form the probes.

If a conventional probe cleaner as described above is used on such aprobe, however, the probe is easily worn out by the cleaning process,its useful lifetime being thus adversely affected. The abraded conditionof a probe also gives rise to the problem of inspection errors on theelectrical characteristics of the chips.

In order to reliably contact the electrode pads on a chip, it has alsobeen known, as shown in FIGS. 5A and 5B, to form indentations 32 and 35or protrusions 31 and 34 on the tip 30 or 33 of a probe, as disclosed inJapanese Patent Publication Tokkai 8-306749.

If these conventional probe cleaners are used to clean the tip part ofsuch a probe, however, foreign objects attached within the indentationsin the tip part cannot be removed sufficiently and the protrusions tendto be worn out by the cleaning process.

SUMMARY OF THE INVENTION

It is therefore an object of this invention to provide a probe cleanercapable of cleaning the tip part of a probe without excessively wearingout the probe by the cleaning process and in particular cleaning the tippart of a probe having indentations or protrusions formed on the tippart.

This invention relates to a probe cleaner and a method of removingforeign objects attached to the tip part of a probe, and in particularto a probe having indentations or protrusions formed at its tip.

A probe cleaner according to this invention is characterized ascomprising a cleaner sheet having a surface part with microfibers andabrading particles affixed to the surface of the microfibers at thissurface part. During a cleaning process, these abrading particlesaffixed to the microfibers at the surface part of the cleaner sheet workon the tip part of the probe to remove the foreign objects attachedthereto.

The average fiber diameter of the microfibers is in the range of 0.1 μmor more and 20 μm or less, and preferably in the range of 0.1 μm or moreand 10 μm or less.

The average particle diameter of the abrading particles is in the rangeof 0.05 μm or more and 3.0 μm or less. The abrading particles of thisinvention include particles of one or more kinds selected from the groupconsisting of alumina, silicon carbide, silicon oxide, zirconia,aluminum hydroxide and diamond.

The cleaner sheet of this invention is a flocked sheet having themicrofibers planted on the surface of a base sheet. The abradingparticles are affixed to the surface of the microfibers of this flockedsheet. These microfibers with abrading particles affixed thereto aremutually independent, not being attached to one another. In other words,these microfibers can move individually, independent of the othermicrofibers.

As a variation, the cleaner sheet of this invention may be a woven ornon-woven cloth sheet comprising microfibers having abrading particlesaffixed thereto.

According to a method of this invention, foreign objects attached to thetip part of a probe are removed by the steps of setting a probe cleanerof this invention to the surface of a table, causing the tip part of theprobe to penetrate into the surface part of the cleaner sheet andcausing the probe to undergo a reciprocal motion in the direction of thethickness of the surface part. The tip part of the probe is thereafterpulled out from the surface part. The probe may be caused to undergo areciprocating motion in the direction of the thickness of the surfacepart while the tip part of the probe remains in the condition ofpenetrating the surface part.

With the invention thus characterized, even a probe having indentationsand protrusions formed at the tip can be cleaned easily without wearingit out excessively.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a sectional view of a probe cleaner of this invention andFIG. 1B is a partially sectional enlarged view of a microfiber.

FIGS. 2A and 2B show a probe being cleaned according to this invention,and FIG. 3 is a schematic drawing of a cleaning apparatus.

FIG. 3 is a microgram of a sectional view of a probe cleaner accordingto this invention.

FIG. 4 is a schematic sectional view of a probe cleaner embodying thisinvention.

FIGS. 5A and 5B are each an enlarged schematic diagonal view of the tipof a probe.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1A and 1B show a probe cleaner 20 embodying this invention forremoving foreign objects attached to the tip part of a probe (shown at12 in FIGS. 2A, 2B and 2C), comprising a cleaner sheet 21 having asurface part 24 comprised of microfibers 25 with abrading particles 26attached to the surface of at least those of the microfibers 25 on thesurface part 24 of this cleaner sheet 21. As shown in FIG. 1B, theabrading particles 26 are affixed to the surface of the microfibers 25by a binder 27.

In the above, the surface part 24 means a portion of the cleaner sheet21 that will work on the tip of the probe 12. The thickness (or theheight) of this surface part 24 is not particularly limited by theinvention and it is sufficient if it has the length of the tip part ofthe probe 12 to be cleaned. It may be in the range of 100 μm or more andless than 1000 μm. As shown in FIGS. 2A and 2B, the cleaning of the tippart of the probe 12 is carried out by sticking the tip part into thesurface part 24 of the cleaner sheet 21 by either moving the table 11 inthe direction of arrow T1 or moving the probe 12 in the direction ofarrow T2. During this cleaning operation, the abrading particles 26affixed to the microfibers 25 at the surface part 24 of the cleanersheet 21 work on the tip part of the probe 12 such that foreign objectsthat may be attached to the tip part of the probe 12 are removed.

The fiber diameter of the microfibers 25 is within the range of 0.1 μmor more and 20 μm or less and preferably 0.1 μm or more and 10 μm orless. Synthetic fibers of nylon, polypropylene, polyethylene,polyethylene terephthalate, polyurethane, acryl, polyvinyl chloride,vinilon or rayon may be used as the microfibers 25.

The size of the abrading particles 26 affixed to the surface of themicrofibers 25 is less than the fiber diameter of the microfibers 25 andpreferably ½ or less of the fiber diameter. This is because if the sizeof the abrading particles 26 is too large, the force for stabilizing theabrading particles against the curved surface of the fiber will becomeweak and the abrading particles working on the tip part of the probe 12may drop off and become attached to the tip part of the probe 12 tobecome foreign objects themselves. Abrading particles with averagediameter in the range of 0.05 μm or more and 3.0 μm or less arepreferred.

No particular limitations are imposed as to the material of the abradingparticles, and particles commonly used for polishing may be used for thepurpose of this invention. Preferable examples include particles ofalumina, silicon carbide, silicon oxide, zirconia, aluminum hydroxideand diamond.

As shown in FIGS. 3 and 4, the cleaner sheet 21 is a flocked sheetcomprising microfibers 25 planted to a base sheet 28 such that theaforementioned abrading particles 26 are affixed to the surface of themicrofibers 25 of this flocked sheet. These microfibers 25 having theabrading particles 26 affixed thereonto are in the condition of notbeing affixed to one another among themselves. In other words, each ofthe microfibers 25 is in the condition of being able to freely moveindependent of the other microfibers 25.

The lengths of the microfibers 25 of the flocked sheet are in the rangeof 100 μm or more and 1000 μm (1.0 mm) or less, and preferably 400 μm ormore and 600 μm or less. If they are too short, this affects the fibermovements adversely. If they are too long, they cannot easily remainindependent and tend to become tangled up such that it becomes difficultto attach the abrading particles 26 to them individually.

As for the base sheet 28, a material with small thermal deformations dueto temperature changes is preferred. A sheet with rate of thermalshrinkage 2% or less in the temperature range of 25° C. or more and 150°or less as its mechanical characteristic is used. No particularlimitations are imposed as to the size and material of the base sheet28. A sheet with thickness in the range of 50 μm or more and 188 μm orless, made of PET (polyethylene terephthalate), PEN (polyethylenenaphthalate), PPS (polyphenylene sulfide, PEI (polyether imide), PI(polyimide), PC (polycarbonate), PVC (polyvinyl chloride), PP(polypropylene), PVDC (polyvinylidene chloride), nylon, PE(polyethylene) or PES (polyether sulfonate) may be used, but a PET sheetis preferred.

As a practical matter, a layer of adhesive agent (referred to as theadhesive layer, shown at 22 in FIG. 1A) is formed on the back surface ofthe base sheet 28, and a peelable paper sheet (shown at 23 in FIG. 1A)is removably pasted to the surface of this adhesive layer 22. Thispeelable paper sheet 23 is peeled off from the surface of the adhesivelayer 22, and the probe cleaner 20 of this invention is thereafterpasted on the table 11 of a probe cleaning apparatus 10 through thisadhesive layer 22, as shown in FIG. 2C.

As a variation, a woven or non-woven cloth sheet made of microfibers 25described above may be used as the cleaner sheet 21 of the probe cleaner20 of this invention. The abrading particles 26 described above areaffixed at least to the surface of the microfibers 25 at the position ofthe surface part 24 of this cleaner sheet 21. This cleaner sheet 21 mayalso have an adhesive layer 22 formed on its back surface so as to bepasted onto the table 11 of the probe cleaning apparatus 10 through thisadhesive layer 22.

As an example of base sheet of this type, too, a sheet with smallthermal deformations due to temperature variations is preferred. Asexplained above with reference to a flocked sheet, there is noparticular limitation as to the size or material of the base sheet ofthis kind. A sheet of synthetic fibers such as polypropylene andpolyethylene with thickness in the range of 50 μm or more and 188 μm orless is used as the base sheet.

In this case, too, a layer of adhesive agent (referred to as theadhesive layer, shown at 22 in FIG. 1A) is formed as a practical matteron the back surface of the base sheet 28, and a peelable sheet (shown at23 in FIG. 1A) is removably pasted to the surface of this adhesive layer22. This peelable paper sheet 23 is peeled off from the surface of theadhesive layer 22, and the probe cleaner 20 of this invention isthereafter pasted on the table 11 of a probe cleaning apparatus 10through this adhesive layer 22, as shown in FIG. 2C.

The probe cleaner 20 of the present invention may be produced bydispersing abrading particles in a liquid resin solution, adding ahardening agent thereto to prepare a paint (coating material), applyingthis paint on the surface of the cleaner sheet 21 by a known coatingmethod such as the reverse roll coating and gravure coating, and dryingit. Examples of the resin solution to be used include one or more resinmaterials selected from polyester resins, polyurethane resins,copolymerized vinyl resins, epoxy resins and phenol resins, dissolved ina solvent. Examples of the solvent include toluene, xylene, MEK(methylethyl ketone), ethyl acetate, cyclohexanone, acetone andalcohols. Examples of hardening agent include isocyanates.

The viscosity of the paint is in the range of 20 cp or more and 300 cpor less, and preferably 50 cp or more and 150 cp or less. If theviscosity of the paint is too low (less than 20 cp), it tends to falldown to the lower layer of the surface part of the cleaner sheet and asufficient amount of the abrading particles 26 cannot be affixed to thesurface of the microfibers 25 at the surface part 24 of the cleanersheet 21. Thus, the abrading particles cannot work sufficiently on thetip part of the probe during a cleaning operation. If the viscosity istoo high (over 300 cp), the paint will remain at the upper layer of thesurface part 24 of the cleaner sheet 21, and a layer with the abradingparticles 26 fastened by the resin (binder 27) is formed such thatmutually adjacent microfibers 25 are attached together. Such a layertends to cause friction on the tip part of the probe 12.

The mix ratio of the abrading particles 26 in the paint is in the rangeof 60 weight % or more, and preferably 80 weight % or more and 98 weight% or less. If the ratio of the abrading particles 26 is too low (lessthan 60 weight %), mutually adjacent microfibers 25 tend to becomeattached to each other to form a layer of the kind described above.

Composition of the paint is shown in Table 1 below. TABLE 1 Abradingparticles 60 weight %-98 weight % Resin solution  1 weight %-35 weight %Hardening agent 1 weight %-5 weight %

As a preferred example, after abrading particles comprising 60 weight%-98 weight % of silicon carbide were heated and dried, they were mixedwith a resin solution obtained by dissolving 1 weight %-35 weight % ofsaturated polyester resin in a mixed solvent of toluene, xylene,ethylene acetate and MEK to disperse the abrading particles in the resinsolution and they were filtered. A paint was prepared immediately beforeit was applied to a cleaner sheet by adding an isocyanate hardeningagent by 1 weight %-5 weight % to adjust the viscosity of the paint to30 cp-150 cp.

As shown in FIG. 2C, the probe cleaner 20 of this invention thusprepared is pasted on the surface of the table 11 through the adhesivelayer (shown at 22 in FIG. 1A). As shown in FIGS. 2A, 2B and 2C, the tippart of a probe 12 is placed on the surface of this cleaner sheet 21 andthe table 11 is moved in the direction of arrow T2 such that the tippart of the probe 12 penetrates into the surface part 24 of the cleanersheet 21. Next, the penetrated tip part of the probe 12 is pulled out ofthe surface part 24 of the cleaner sheet 21 by moving the table 11 inthe direction of arrow T1. By this reciprocating motion of the table 11in the directions of arrows T1 and T2, foreign objects attached to thetip part of the probe 12 are removed by the surface part 24.

Cleaning tests were carried out by preparing probe cleaners of Test andComparison Examples and using these prepared probe cleaners to removeforeign objects from the tip parts of probes having indentations andprotrusions at the tips. After these probes were cleaned, they werecompared regarding the removal rate from these indentations andprotrusions, and the presence or absence of wears (abrasions) wasexamined by visual observation with a microscope.

FIGS. 4A and 4B show the tips of the two kinds of probes Test Probes Aand B used for the cleaning test. The tip of Test Probe A is shown inFIG. 5A, having an indentation and a protrusion. The size of its bottomsurface is about 90 μm×90 μm, its height is about 70 μm, the diameter ofits indentation is about 50 μm, and its depth is about 70 μm. With TestProbe A, the periphery of this indentation forms its protrusion.

The tip of Test Probe B is shown in FIG. 5B, having a plurality ofindentations and protrusions. Its bottom surfaces are about 30 μm×30 μmand its height is about 100 μm. Indentations are formed as valleysbetween the protrusions.

A cleaning apparatus as shown in FIG. 2C was used for the cleaning testunder the same conditions for both Test and Comparison Examples. Whenthe contact frequency of the probes to the cleaner sheet of the probecleaner became 1000 times, 10000 times and 100000 times, the abradedcondition of the tip of the probe was observed and the presence andabsence of foreign objects attached to the indentation-protrusion at thetip of the probe was observed when the contact frequency reached 100000times.

TEST EXAMPLE 1

A probe cleaner of Test Example 1 was prepared as follows.

A paint was prepared by heating and drying 1 kg of abrading particles ofsilicon carbide with average diameter of 0.05 μm, thereafter mixing themwith a resin solution obtained by dissolving 310 g of saturatedpolyester resin in a mixed solvent of toluene, xylene, ethyl acetate andMEK, stirring it to disperse the abrading particles in the resinsolution and thereafter filtering them, and adding 60 g of an isocyanatehardening agent and adjusting it immediately before it is applied ontothe cleaner sheet. Its viscosity was 50 cp.

The paint was applied to the surface of each of the microfibers on thesurface part of the flocked sheet and dried to produce a probe cleaner.

Application of the paint was carried out by using a gravure roller (#50having grooves in straight lines at regular intervals making angles of45°).

The flocked sheet was of a PET sheet of thickness 50 μm havingmicrofibers with average fiber diameter of 10 μm and average length 500μm (500 μm±100 μm) planted.

TEST EXAMPLE 2

The probe cleaner of Test Example 2 was prepared by using the samematerial and by the same method as for Test Example 1 except that theaverage diameter of the abrading particles was changed to 0.3 μm.

TEST EXAMPLE 3

The probe cleaner of Test Example 3 was prepared by using the samematerial and by the same method as for Test Example 1 except that theaverage diameter of the abrading particles was changed to 3 μm.

TEST EXAMPLE 4

The probe cleaner of Test Example 4 was prepared by using the samematerial and by the same method as for Test Example 1 except thatmicrofibers with average fiber diameter of 0.1 μm were used for theflocked sheet.

TEST EXAMPLE 5

The probe cleaner of Test Example 5 was prepared by using the samematerial and by the same method as for Test Example 1 except thatmicrofibers with average fiber diameter of 3 μm were used for theflocked sheet.

TEST EXAMPLE 6

The probe cleaner of Test Example 6 was prepared by using the samematerial and by the same method as for Test Example 1 except thatmicrofibers with average fiber diameter of 20 μm were used for theflocked sheet.

TEST EXAMPLE 7

The probe cleaner of Test Example 7 was prepared by using the samematerial and by the same method as for Test Example 1 except thatalumina was used as abrading particles.

TEST EXAMPLE 8

The probe cleaner of Test Example 8 was prepared by using the samematerial and by the same method as for Test Example 1 except thatdiamond was used as abrading particles.

COMPARISON EXAMPLE 1

The probe cleaner of Comparison Example 1 was prepared by using the samematerial and by the same method as for Test Example 1 except that theaverage diameter of the abrading particles was changed to 5 μm.

COMPARISON EXAMPLE 2

A probe cleaner of Comparison Example 2 was prepared as follows.

A paint for aforementioned Test Example 3 (prepared by heating anddrying 1 kg of abrading particles of silicon carbide with averagediameter of 3 μm, thereafter mixing them with a resin solution obtainedby dissolving 310 g of saturated polyester resin in a mixed solvent oftoluene, xylene, ethyl acetate and MEK, stirring it to disperse theabrading particles in the resin solution and thereafter filtering them,and adding 60 g of an isocyanate hardening agent and adjusting itimmediately before it is applied onto the cleaner sheet, and having aviscosity of 50 cp) was applied to the surface of a PET film by using agravure roller (#50 having grooves in straight lines at regularintervals making angles of 45°) and dried.

COMPARISON EXAMPLE 3

A probe cleaner of Comparison Example 3 was prepared by applying a paintfor aforementioned Test Example 3 to the surface of a foamed film byusing a gravure roller (#50 having grooves in straight lines at regularintervals making angles of 45°) and drying.

The compositions of the probe cleaners of Test Examples 1-8 andComparison Examples 1-3 are summarized in Table 2 below. Results of thetest are shown in Table 3 below. TABLE 2 Sheet Abrading particles Fiberdiameter Average diameter Type (μm) Material (μm) Test Example 1 Flockedsheet 10 Silicon carbide 0.05 Test Example 2 Flocked sheet 10 Siliconcarbide 0.3 Test Example 3 Flocked sheet 10 Silicon carbide 3 TestExample 4 Flocked sheet 0.1 Silicon carbide 0.05 Test Example 5 Flockedsheet 3 Silicon carbide 0.05 Test Example 6 Flocked sheet 20 Siliconcarbide 0.05 Test Example 7 Flocked sheet 10 Alumina 0.3 Test Example 8Flocked sheet 10 Diamond 0.3 Comparison Example 1 Flocked sheet 10Silicon carbide 5 Comparison Example 2 PET film — Silicon carbide 3Comparison Example 3 Foamed film — Silicon carbide 3

TABLE 3 Test Probe A Test Probe B Removal rate Removal rate from Wearson from Wears on indentations indentations indentations protrusions TestExample 1 C A C A Test Example 2 B B B B Test Example 3 A C A C TestExample 4 B A B A Test Example 5 A A A A Test Example 6 B A B A TestExample 7 C A C A Test Example 8 A C A C Comparison A D A D Example 1Comparison D A D D Example 2 Comparison D B D D Example 3

In Table 3, the symbols for the removal rate of foreign objects fromindentations are as follows:

A: 95% and over

B: 80-95%

C: 60-80%

D: Below 60%

The symbols for the wears (abrasions) are as follows:

A: No wears after 100000 contacts

B: Wears appear after 100000 contacts

C: Wears appear after 10000 contacts

D: Wears appear after 1000 contacts

It can be seen from the results of Test Examples 1-3 and ComparisonExample 1 that the removal rate from indentations drops as the diametersof the abrading particles are made smaller, becoming 60-80% with averageparticle diameter of 0.05 μm (Test Example 1). The wears become smalleras the diameters of abrading particles are made larger, becoming notdetectable after 10000 contacts with average particle diameter of 0.05μm (Test Example 3) and after 1000 contacts with average particlediameter of 5 μm (Comparison Example 1).

The results of Test Examples 2, 7 and 8 show that no significant changesappear in the removal rate of foreign objects in indentations and thedegree of wears even if the kind of abrading particles is changed andthat results better than by Comparison Examples can be obtained.

The results of Test Examples 1 and 4-6 show that the removal rate offoreign objects in indentations becomes lower if the fiber diameter isreduced, becoming 80-95% if the fiber diameter is 0.1 μm (TestExample 1) and that the wears begin to appear when the contact numberreaches 10000 if the fiber diameter exceeds 110 μm and becomes 20 μm. Onthe other hand, the amount of wears does not depend very much on thefiber diameter, no wears being detectable after 100000 contacts if thefiber diameter is in the range of 0.1 μm-20 μm.

From the above, it may be concluded that it is preferable to usemicrofibers with fiber diameters of 0.1 μm-20 μm for the flocked sheetand abrading particles with average particle diameter of 0.05 μm-3 μm tobe affixed to these microfibers.

The results of Table 3 generally show that the probe cleaners of TestExamples 1-8 have better removal rates of foreign objects inindentations than those of Comparison Examples, causing less wears onthe indentations and protrusions on the probe.

Although probe cleaners and cleaning methods were described above forthe tip part of a probe, it goes without saying that the presentinvention can be used for the removal of foreign objects attached to thetip part of other kinds of needle such as needles for clinical use andfor sewing.

1. A probe cleaner for removing foreign objects attached to the tip partof a probe, said probe cleaner comprising: a cleaner sheet having asurface part with microfibers; and abrading particles affixed to thesurface of the microfibers at said surface part.
 2. The probe cleaner ofclaim 1 wherein said microfibers have average fiber diameter in therange of 0.1 μm or more and 20 μm or less.
 3. The probe cleaner of claim1 wherein said microfibers have average fiber diameter in the range of0.1 μm or more and 10 μm or less.
 4. The probe cleaner of claim 1wherein the average particle diameter of said abrading particles is inthe range of 0.05 μm or more and 3.0 μm or less.
 5. The probe cleaner ofclaim 1 wherein said abrading particles include particles of one or morekinds selected from the group consisting of alumina, silicon carbide,silicon oxide, zirconia, aluminum hydroxide and diamond.
 6. The probecleaner of claim 1 wherein said cleaner sheet is a flocked sheet havingsaid microfibers planted on the surface of a base sheet.
 7. The probecleaner of claim 1 wherein said cleaner sheet is a woven or non-wovencloth sheet comprising said microfibers.
 8. The probe cleaner of claim 1wherein said probe has indentations or protrusions at the tip.
 9. Amethod of removing foreign objects from the tip part of a probe, saidmethod comprising the steps of: setting a probe cleaner to the surfaceof a table, said probe cleaner comprising a cleaner sheet having asurface part with microfibers and abrading particles affixed to thesurface of the microfibers at said surface part; causing said tip partof said probe to penetrate inside said surface part; and causing saidprobe to undergo a reciprocal motion in the direction of the thicknessof said surface part.
 10. The method of claim 9 further comprising thestep of pulling out said probe from said surface part.
 11. The method ofclaim 9 wherein said reciprocal motion is caused while said tip part ofsaid probe remains in the condition of penetrating inside said surfacepart.
 12. The method of claim 9 wherein said probe has indentation orprotrusion at said tip.